If you change the stack at TCP level... - How many hardware network components would need replacing/upgrading to support a layer not expected to change? - How

If you change the stack at TCP level... - How many hardware network components would need replacing/upgrading to support a layer not expected to change? - How many network + application software libraries would need to support parsing at packet level instead of byte level? - How many OSI diagrams showing that high level byte and string based protocols run above the transport layer need to be re-written to say that's no longer the case. - How many versions of RPC would need to be supported... just look at the numerous revisions of CORBA/RMI/SOAP(Document or RPC Style!)/REST/GRPC to see how many times you can re-invent (and misinterpret, break standards of) a wheel. - Look how long IPv6 needed buy in and refinement, and then adoption. That was a necessary change with no alternative too! There are many applications that shouldn't need TCP, such as those only doing short network hops or needing real time traffic with expected packet loss. They should use UDP but often don't. TCP is ubiquitous for the very reason that it is the chameleon mentioned in the article - TCP is not ideal, but it is convenient and well understood.